Parts Catalog Accessories Catalog Tech Info Tech Forums
 
  Search our site:    
 Cart  | Project List | Order Status | Help    
  We salute a legendary member of the community.
Thank you for selflessly sharing your wisdom with us...
Go Back   Pelican Parts Technical BBS > 1- Porsche Technical Forums > 911 / 930 Turbo & Super Charging Forum

Reply
 
LinkBack Thread Tools Rating: Thread Rating: 1 votes, 3.00 average.
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Mar 2011
Location: Toronto
Posts: 153
Garage
Need advice...going lean over 5k rpm

Here's the background. I bought my car last fall and it needed a rebuild as the rings were cooked from going lean on top end, but could not be seen as no AFR gauge.
So it is now rebuilt to 3.3L, new 964 cams from Andial, new rockers,valve guides, recut valve seats, etc. It has Andail racing intercooler and Garrett GT3582R turbo set to 0.8 bar. I also install a Innovate AFR gauge.

Here are the 2 problems:
  • Start the car cold, the idle is 400 rpm and sputters on acceleration. Once warm its spot on with 1000 rpm idle. Why poor when cold?
  • Next and main problem. AFR is 14.6-14.8 off boost and 11.2-12 on boost until 5k rpm then it start to lean out quick. Soon as I see AFR of 13 I lift off and this depends on the ambient air temp but this week has been around 5300 rpm when starting to get these AFRs ??

Is my WUR the issue? My mechanic has said that someone has been monkeying with the fuel pressure regulator and is the reason for the poor cold starts.

Your advice would be great. Thx.
Old 08-17-2012, 04:26 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #1 (permalink)
Registered User
 
xbmwguy's Avatar
 
Join Date: Apr 2008
Location: west palm beach fla
Posts: 963
Garage
thank god you got the afr guage or you would be doing it again . that turbo needs fuel up top. i would highly recomend a brian leaske adjustable warm up regulator in conjunction with a moddified fuel head from larry at flowtech. this will save your motor and keep you having fun at higher rpms
Old 08-17-2012, 06:25 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #2 (permalink)
Registered User
 
Join Date: Jul 2006
Location: S. Florida
Posts: 5,601
What is the AFR gauge saying during the 400 rpm, sputtering cold start?
The rest of your AFR's sound normal for stock CIS.

Frank is right and that'll cost around $1000 with shipping if you do the work yourself.

or...

You could sell all the old CIS and distributor ignition stuff and switch to versatile and tunable EFI and crankfire ignition and the results may blow your mind . . .
Old 08-17-2012, 07:09 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Mar 2011
Location: Toronto
Posts: 153
Garage
Definitely cant go EFI, would love to but the obvious $$$$
If I get the BL WUR and leave the current fuel head will that work?

Also, I have read on BL WUR and I am unsure about the RPM clamp. I see the benefits when driving flat out to pick an rpm to trigger the fuel enrichment, but I am finding during regular driving that i am not always on boost in the higher rpms are I may be holding my speed. Does this rpm clamp work inline with the map sensor to trigger the enrichment?

Thanks for the feedback so far guys!
Old 08-17-2012, 07:32 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #4 (permalink)
Registered User
 
Join Date: Mar 2011
Location: Toronto
Posts: 153
Garage
JFairman, the AFR is reading 13-15 range when idling at 400 rpm.
Old 08-17-2012, 07:34 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #5 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 11,172
Garage
Cold start issue is likely high cold pressure.

Lean boost issue may be fixed with an adjustable WUR and rpm switch. We handle those if interested. Cold and warm pressure is also adjustable on those units.

You won't know if you need a modified fuel head until the WUR pressures are adjusted and AFR data collected. I've seen too many folks with modded fuel heads that don't need them; we rebuild them back to OEM and all is well. We also handle OEM and modified fuel heads and have them in stock.

EFI is great if DIY, a potential nightmare if farmed out. $1000 for rebuilding the fuel head and WUR and you get a great running engine capable of 21mpg and 400WHP or spend $10,000+ and maybe a year later you get your car back and it runs like **** and never gets sorted out properly as only one shop can do it. DO a LOT of homework if even considering EFI.
__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 08-17-2012, 07:48 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #6 (permalink)
 
Now Available for Ordering:   101 Projects For Your BMW 3 Series 1982-2000  [more info]
Registered User
 
Join Date: Mar 2011
Location: Toronto
Posts: 153
Garage
Thanks Brian, I did get a quote from you on the WUR. Can you answer my question about the rpm switch?
Old 08-17-2012, 07:59 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #7 (permalink)
Registered User
 
heliolps2's Avatar
 
Join Date: Jan 2009
Location: VA
Posts: 590
Garage
I think what going on with your cold start is that you most likely have the vacuum hose or hoses plumed incorrectly , what is happening is that your get vacuum on the retard side to your disribulator and what that does is retards your trimming and causes the low rpm when cold , as for you going lean on top ,it could be that your system pressure is to high , that is easily adjusted by removing or replaceing the shims with thinner ones one the fuel head , you will need CIS test gauge , the other thing you should check is the voltage going to the fuel pumps , as these cars get older the wiring get weaker , and cause low voltage and what would happen you run out of fuel on top,
__________________
Helio"s 1976 911S, 911GT AIR Bodie, 930/66 motor,CIS, 428 fwhp 490TQ at 4200rpm's, Raceware bolts, Carrillo rods, 964 cams, Assco springs ,TT retainers,7.5 comp 1.1 bar boost 320 ml black fuel head 009 injectors, 044 pumps, 60-1 T4/T3 dual scroll turbo, G50 8:32 ring & pin KEP 600 lite clutch ,Bilstien coil overs ,935 spring plates,Big Reds brakes,993 interior, 2698 lbs wet
Old 08-17-2012, 08:27 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #8 (permalink)
Registered User
 
heliolps2's Avatar
 
Join Date: Jan 2009
Location: VA
Posts: 590
Garage

__________________
Helio"s 1976 911S, 911GT AIR Bodie, 930/66 motor,CIS, 428 fwhp 490TQ at 4200rpm's, Raceware bolts, Carrillo rods, 964 cams, Assco springs ,TT retainers,7.5 comp 1.1 bar boost 320 ml black fuel head 009 injectors, 044 pumps, 60-1 T4/T3 dual scroll turbo, G50 8:32 ring & pin KEP 600 lite clutch ,Bilstien coil overs ,935 spring plates,Big Reds brakes,993 interior, 2698 lbs wet
Old 08-17-2012, 08:50 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #9 (permalink)
Registered User
 
heliolps2's Avatar
 
Join Date: Jan 2009
Location: VA
Posts: 590
Garage
__________________
Helio"s 1976 911S, 911GT AIR Bodie, 930/66 motor,CIS, 428 fwhp 490TQ at 4200rpm's, Raceware bolts, Carrillo rods, 964 cams, Assco springs ,TT retainers,7.5 comp 1.1 bar boost 320 ml black fuel head 009 injectors, 044 pumps, 60-1 T4/T3 dual scroll turbo, G50 8:32 ring & pin KEP 600 lite clutch ,Bilstien coil overs ,935 spring plates,Big Reds brakes,993 interior, 2698 lbs wet
Old 08-17-2012, 08:59 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #10 (permalink)
Registered User
 
Join Date: Mar 2011
Location: Toronto
Posts: 153
Garage
What should the fuel pump voltage be? 12v ?A
I will double check the vacuum lines.

Still want to understand if the BL rpm switch works inline with the map sensor? Does it trigger full boost enrichment from the set rpm on, regardless if there is boost or not?
I much not be understand this correct, please help me understand.
Old 08-17-2012, 12:38 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #11 (permalink)
I've gone native
 
Tt surgeon's Avatar
 
Join Date: Sep 2011
Location: Long Island, NY
Posts: 1,540
I would listen to Brian on this one.
Old 08-17-2012, 12:50 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #12 (permalink)
Tinkering Pays!!
 
mooney265's Avatar
 
Join Date: Sep 2008
Location: New Orleans
Posts: 1,248
Garage
Quote:
Originally Posted by flat_6 View Post
What should the fuel pump voltage be? 12v ?A
I will double check the vacuum lines.

Still want to understand if the BL rpm switch works inline with the map sensor? Does it trigger full boost enrichment from the set rpm on, regardless if there is boost or not?
I much not be understand this correct, please help me understand.
Brian could better answer that. But, I have one, so I'll take a go at it: the rpm switch "DELAYs" the full enrichment that would otherwise come too early in the rpm band. You can choose when to "delay" by choosing different rpm pills [ie 4000, 4500, 5000 etc]

Hope that helps...
__________________
LIVN80S - - Red '79 Porsche 930 Steel Slant Nose Conversion [in 1987] w. 46k miles 3.3L; 964 Cams; K27HF @ 1.0 BAR, with Garrettson Intercooler; Rarly Zork; CIS Flowtech Fuel Head & BL-WUR.
Old 08-17-2012, 12:53 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #13 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 11,172
Garage
Yes that is the effect.
The WUR will dump fuel starting at ~0.3bar causing the midrange to be very rich. The RPM switch is plugged into the vac/boost port of the WUR and blocks that signal until the predetermined RPM is reached. You set that RPM based on where the fuel dump starts and then leans out on the AFR graph of your engine. By holding off enrichment you can smooth the midrange gaining torque and wasting less fuel. The top end adjustment is independent.
__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 08-17-2012, 01:13 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #14 (permalink)
Registered User
 
heliolps2's Avatar
 
Join Date: Jan 2009
Location: VA
Posts: 590
Garage
Ok , try this , before you start your car when it cold pull the vacuum hose off the dizzy , pull the one closest to the center of the engine, then start the car , the rmps should be at 1200 to 1000 rmps , if that happens the you know that we are on the right track, I had 6 other 930 at my home with the same problems they start and drive fine now. Call me any time 210-473-7158 Helio
__________________
Helio"s 1976 911S, 911GT AIR Bodie, 930/66 motor,CIS, 428 fwhp 490TQ at 4200rpm's, Raceware bolts, Carrillo rods, 964 cams, Assco springs ,TT retainers,7.5 comp 1.1 bar boost 320 ml black fuel head 009 injectors, 044 pumps, 60-1 T4/T3 dual scroll turbo, G50 8:32 ring & pin KEP 600 lite clutch ,Bilstien coil overs ,935 spring plates,Big Reds brakes,993 interior, 2698 lbs wet
Old 08-18-2012, 06:52 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #15 (permalink)
Registered User
 
Join Date: Mar 2011
Location: Toronto
Posts: 153
Garage
You guys are awesome. Thx.
Brian, I will be calling you Monday to order a Adj. WUR and rpm switch.
Do I need any other info from my car first?
Old 08-18-2012, 07:45 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #16 (permalink)
Registered User
 
beepbeep's Avatar
 
Join Date: Jun 2001
Location: Sweden
Posts: 5,293
Send a message via ICQ to beepbeep
930 motor with stock cams has such atrocious VE at high RPM's that slight leaning on the top isn't really such a issue that one might think.

Factory knew this and made it run rich where VE (and thus torque) is highest. At 6000 RPM, turbo is trying to cram air into cylinders but it just cannot do it well, due to port size and cam timing. I know many look at stock AFR's and think "ooh, it goes so fat in the middle and then leans out" but if you look at torque curve (and corresponding cylinder pressures) you see that it goes fat when it has to.
If it's going to ping, it will mostly do it at 4000-5000 RPM.

P.S. Change cam timing and/or intake/exhaust tuning and it all goes out of the window.
__________________
Thank you for your time,

Last edited by beepbeep; 08-18-2012 at 07:56 AM..
Old 08-18-2012, 07:53 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #17 (permalink)
Registered User
 
Join Date: Mar 2011
Location: Toronto
Posts: 153
Garage
Helio, I pull off the vacuum line you suggested and you are right. It idles at 1000-1200 rpm.
Hooked it back up and back to 500 ish.
Now what?
Old 08-18-2012, 08:02 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #18 (permalink)
Registered User
 
heliolps2's Avatar
 
Join Date: Jan 2009
Location: VA
Posts: 590
Garage
Give me a call 210 473 7158
__________________
Helio"s 1976 911S, 911GT AIR Bodie, 930/66 motor,CIS, 428 fwhp 490TQ at 4200rpm's, Raceware bolts, Carrillo rods, 964 cams, Assco springs ,TT retainers,7.5 comp 1.1 bar boost 320 ml black fuel head 009 injectors, 044 pumps, 60-1 T4/T3 dual scroll turbo, G50 8:32 ring & pin KEP 600 lite clutch ,Bilstien coil overs ,935 spring plates,Big Reds brakes,993 interior, 2698 lbs wet
Old 08-18-2012, 08:12 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #19 (permalink)
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 11,172
Garage
Goran/Beep has a good point and you do want to keep the midrange more fat than the top end, which is easy to do given the characteristics. I like low to mid 11's in the midrange and 12 at redline.

Helio's vac line swap does work, however if your engine used to run good when cold and now does not you need to fix that problem first before swapping vac ports.
__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 08-18-2012, 01:40 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #20 (permalink)
Old 08-18-2012, 01:40 PM
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 


All times are GMT -8. The time now is 01:53 AM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.